Performance of Erbium-doped TiO2 thin film grown by physical vapor deposition technique

Abstract

Undoped and Erbium-doped TiO2 thin films (Er:TiO2 TFs) were fabricated on the n-type Si substrate using physical vapour deposition technique. Field emission scanning electron microscope showed the morphological change in the structure of Er:TiO2 TF as compared to undoped sample. Energy dispersive X-ray spectroscopy (EDX) confirmed the Er doping in the TiO2 thin film (TF). The XRD and Raman spectrum showed the presence of anatase phase TiO2 and Er2O3 in the Er:TiO2 TF. The Raman scattering depicted additional number of vibrational modes for Er:TiO2 TF due to the presence of Er as compared to the undoped TiO2 TF. The UV–Vis absorption measurement showed that Er:TiO2 TF had approximately 1.2 times more absorption over the undoped TiO2 TF in the range of 300–400 nm. The main band transition, i.e., the transition between the oxygen (2p) state and the Ti (3d) state was obtained at ~3.0 eV for undoped TiO2 and at ~3.2 eV for Er:TiO2 TF, respectively. The photo responsivity measurement was done on both the detectors, where Er:TiO2 TF detector showed better detectivity (D *), noise equivalent power and temporal response as compared to undoped detector under ultra-violet illumination.